The Nets signed free-agent forward Yuta Watanabe on Sunday, filling one of what had been an NBA-high six open roster spots.

The 27-year-old Watanabe received one of the Nets’ two available standard deals, albeit a non-guaranteed one-year contract, according to a league source. They now have 14 of their 15 standard spots spoken for.

The Nets still have all three Exhibit 10 spots open, one of their pair of two-way deals left and a lone standard contract left to give. David Duke Jr. — a restricted free agent — has turned down their two-way offer in hopes of landing a standard deal. The addition of Watanabe severely cuts into his chances.

Watanabe has played 121 games (with eight starts) in four NBA seasons, the first two years with the Memphis Grizzlies and the last two for the Toronto Raptors. He’s averaged 3.8 points and 2.5 rebounds over 12.0 minutes for his career, and 4.3 points with 2.4 boards last season for the Raptors.

The 6-foot-9, 214-pounder played for Brooklyn in Las Vegas Summer League in 2018 after going undrafted out of George Washington. The first Asian player inked by the Nets since Joe Tsai took over in 2019, Watanabe has played for the Japanese National Team, leading it in scoring in the 2019 FIBA Basketball World Cup.

The Nets are still looking to add another veteran big man at either center or power forward, according to sources.